An interior furnishing part for use in motor vehicles is provided in its method of fabrication with a decorative or attachment seam.
The invention is directed to a method of manufacturing interior furnishing parts for motor vehicles with the parts being provided with a decorative or attachment seam. The furnishing part has a material sheet formed into its intended final shape in a molding operation using a male or female mold. The material sheet forms the exterior or outside surface of the part and is backed by a support part or material with the possibility of inserting padding between the outside material sheet and the support material. The padding can be a foamed material. After the molding step, the furnishing part is provided with a decorative or attachment seam.
Interior furnishing parts for vehicles, such as foam-backed interior linings, dashboards, and upholstery parts, are usually manufactured in a female mold containing a molding cavity. Initially, a cover sheet forming the visible exterior of the interior furnishing part is inserted into the mold and a support is placed on it and finally, after the mold is closed, the covering material is connected or bonded to the support part by foaming a foamable material introduced between the two parts, so that the interior furnishing part is provided with its intended final shape. With such a process it is possible to manufacture large area interior furnishing parts with a three-dimensional curved surface when utilizing single or multiple part covering material blanks and providing a padding or foam backing material of variable thickness.
The formation of ornamental or decorative seams prior to the molding step on an interior furnishing part is complicated by the fact that an adequate centering of the mold is not possible in a simple manner, so that a straight line run of the seam parallel to a groove in the mold is not assured and can not be effected in mass production. It is known in the fabrication of foam backed upholstery parts, such as in DE-PS 37 43 318, to fix or attach a cover, formed of individual portions of a covering material connected to one another by seams, at protruding ribs of a deep drawing mold for assuring a correct run of the seams on the finished part. Such a process, however, requires a considerable expenditure of time in preparing the mold and of the use of the machinery, since the fixation of the seams in the mold at its ribs requires the use of a gripper arrangement having a complicated structure. If the covering material is leather or a natural or synthetic material, it is also necessary in the known method to seal the seam before backing it with foam, to prevent the foamed material from penetrating through the needle holes. Accordingly, this known method is too expensive and inaccurate for locating purely decorative or ornamental seams.